JS Practice — Built-in Objects

String.fromCodePoint() — string length with emoji

📖 Usage Example

String.fromCodePoint(65)       // → 'A'
String.fromCodePoint(9731)     // → '☃'
String.fromCodePoint(128512)   // → '😀'

Use String.fromCodePoint() to create a string from Unicode code point values, including characters outside the BMP.

String.fromCodePoint() — Length of Supplementary Characters

A supplementary character (code point > U+FFFF) counts as 2 in .length because JavaScript strings are UTF-16 and the character uses a surrogate pair.

Challenge: Implement emojiLength(cp) that returns the .length of the string produced by String.fromCodePoint(cp).

emojiLength(65)     // → 1
emojiLength(128512) // → 2

💡 Hints (1)

• JavaScript `.length` counts UTF-16 code units, not code points.